BPN350: A Ferrofluid Immunoassay Based on Magnetic Field-Induced Birefringence

Project ID

BPN350

Website

Start Date

Sun 2006-Jul-30 23:16:54

Last Updated

Mon 2008-Jan-28 09:01:51

Abstract

This project exploits the unique properties of magnetic
nanoparticles (MNP) to develop a new type of biological assay. In the
proposed assay, binding events between biological molecules and
functionalized MNPs are detected by changes in the frequency-dependent
magnetic relaxation signal of the MNPs. The relaxation time is determined
by Brownian rotation of the particles in solution and is directly
proportional to the particle volume. By appropriate selection of the
particle properties, nanometer-scale changes in particle diameter can be
detected. The detection method relies on a sinusoidal frequency sweep of
the magnetic field and optical readout - the MNP become birefringent under
an applied field, allowing highly sensitive measurements to be made with a
simple optical setup and greatly facilitating later on-chip
miniaturization.